#define _CRT_SECURE_NO_WARNINGS

#include <stdio.h>

int getScore(char g)
{
	switch (g)
	{
	case 'A':
		return 95;
		break;
	case 'B':
		return 85;
		break;
	case 'C':
		return 75;
		break;
	case 'D':
		return 65;
		break;
	case 'E':
		return 40;
		break;
	}
	
}

int main()
{
	char ch;
	float sum = 0, avg = 0;
	int i = 0;
	int ele = 0;
	while (scanf("%c", &ch), ch != '\n')
	{
		ele = getScore(ch);
		sum += ele;
		i++;
	}

	avg = sum / i;
	printf("%.1f", avg);
	return 0;
}